It is often desirable or convenient to transport audio or video information from one device to another. For example, music stored on a home device may be copied to a medium for playing in an automobile. In the past, such a transfer of music might be accomplished by recording from an analog vinyl disk onto an audio cassette which could be played in the automobile. The owners of the copyrights in the music material could be reasonably sure that the music could not be usefully replicated to many generations, because inexact analog reproduction and the multiplication of noise would degrade the quality of the performance after a few generations.
With the advent of digital recording and storage, the potential exists for the making of many generations of essentially perfect copies of information, be it audio or video. Various schemes have been suggested and implemented in attempts to limit the unauthorized copying of digitally recorded entertainment media.
Improved and/or alternative arrangements are desired for secure porting of digital information.